Hitherto, in a system for operating a screen through use of a controller via an apparatus main unit, the controller itself does not have a function of communicating to/from a network, and hence a controller dedicated to the apparatus main unit is directly connected to the apparatus main unit. Therefore, when a plurality of controllers are connected to the apparatus main unit through a network existing outside the apparatus main unit, an apparatus main unit needs to be provided for each of the plurality of controllers.
In particular, there is known a head-mounted display (HMD) to be worn around a head of a user to allow an image to be presented to the user by a display or the like placed in front of his or her eyes. The related-art HMD requires a controller dedicated to an apparatus main unit.